The Difference between commonly used Sulfonating reagents

Strong cation exchange packing is a very important type of chromatographic packing. It mainly uses sulfonation reagent to sulfonate the surface of polymer-based spheres, and connects the sulfur atoms of sulfonic acid groups with carbon atoms in organic molecules through chemical bonds. The sulfonic acid groups were grafted onto the surface of the microspheres to give them hydrophilic properties.

The commonly used sulfonation methods in industry mainly include SO3 sulfonation method, sulfuric acid sulfonation method, chlorosulfonic acid sulfonation method, sulfite sulfonation method, etc., while the commonly used sulfonation reagents mainly include SO3, concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid, sulfite, etc. Different sulfonation reagents lead to different sulfonation processes. In practical application, the corresponding sulfonation reagents and sulfonation methods should be selected according to the needs of application scenarios and application objectives.

1. SO₃

SO₃ is the earliest sulfonation reagent. After years of development, four sulfonation processes have been developed: gaseous SO₃ sulfonation, liquid SO₃ sulfonation, SO₃ solvent sulfonation, and SO₃ complex sulfonation .

The gaseous method has fast reaction, less three wastes, less corrosion to equipment and advanced technology. It is the most widely used sulfonation method at present. However, because gaseous SO₃ is too active and the reaction is violent, it is easy to cause local overheating and excessive sulfonation, which will affect product performance. Influence.

Due to the violent reaction, the liquid method has relatively high requirements on the reactants, and is suitable for the sulfonation of relatively stable aromatic compounds. The liquid method has a complicated process, and only a few domestic companies use this method to sulfonate benzene compounds.

The solvent method is further divided into organic solvent and inorganic solvent method. The former mostly uses sulfuric acid and has strong versatility. The latter are mostly alkanes and various ethers.

The complex method has mild reaction, good selectivity, few by-products, and high product purity, but the cost is very high, so it is mainly used for the preparation of small batches of products.

2. Sulphuric acid

The traditional sulfonation reaction mostly uses sulfuric acid as the sulfonating agent, and the sulfuric acid includes concentrated sulfuric acid and oleum. The sulfuric acid method has mild reaction, few by-products, and is easy to control. However, the acid consumption of the reaction is huge, and the waste liquid treatment cost is high. Nevertheless, this method is still used in the industry.

3. Chlorosulfonic acid

When chlorosulfonic acid is used as a sulfonating agent, the reaction is more active, the by-product HCl is easy to discharge, and the reaction can be carried out at room temperature, and the product is light in color and high in purity. many.

4. Sulfite

When sulfite is used as sulfonating agent, it is suitable for sulfonation reaction mainly based on nucleophilic substitution, such as sodium sulfite.

In addition to the above-mentioned sulfonation reagents and sulfonation methods, there are other reagents and methods with less application. In short, different sulfonation reagents are suitable for different scenarios and should be selected in a targeted manner.

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